Right angle coaxial cable and connector assembly

ABSTRACT

Coaxial cable-connector assemblies include: a coaxial cable having: an inner conductor having a termination end including a bore; a dielectric layer that overlies the inner conductor; and an outer conductor that overlies the dielectric layer having a termination end; a right angle coaxial connector including: an inner conductor body with a post configured to mate with the inner conductor body of a mating jack, the inner conductor body further including a receptacle that receives the termination end of the inner conductor such that the post is generally perpendicular to the inner conductor; an outer conductor body configured to mate with the outer conductor body of the mating coaxial cable jack and electrically connected with the termination end of the outer conductor; and an expansion member inserted into the bore of the termination end of the inner conductor sized and configured to radially expand the termination end of the inner conductor.

RELATED APPLICATION

The present application claims the benefit of and priority from U.S.Provisional Patent Application No. 62/111,944, filed Feb. 4, 2015 and isa continuation of U.S. patent application Ser. No. 14/996,942, filedJan. 15, 2016, the disclosures of which are hereby incorporated hereinby reference in their entireties.

FIELD OF THE INVENTION

The present invention is directed generally to electrical cableconnectors, and more particularly to coaxial connectors for electricalcable.

BACKGROUND OF THE INVENTION

Coaxial cables are commonly utilized in RF communications systems. Atypical coaxial cable includes an inner conductor, an outer conductor, adielectric layer that separates the inner and outer conductors, and ajacket that covers the outer conductor. Coaxial cable connectors may beapplied to terminate coaxial cables, for example, in communicationsystems requiring a high level of precision and reliability.

Coaxial connector interfaces provide a connect/disconnect functionalitybetween (a) a cable terminated with a connector bearing the desiredconnector interface and (b) a corresponding connector with a matingconnector interface mounted on an apparatus or on another cable.Typically, one connector will include a structure such as a pin or postconnected to an inner conductor and an outer conductor connector bodyconnected to the outer conductor; these are mated with a mating sleeve(for the pin or post of the inner conductor) and another outer conductorconnector body of a second connector. Coaxial connector interfaces oftenutilize a threaded coupling nut or other retainer that draws theconnector interface pair into secure electro-mechanical engagement whenthe coupling nut (which is captured by one of the connectors) isthreaded onto the other connector.

Passive Intermodulation Distortion (PIM) is a form of electricalinterference/signal transmission degradation that may occur with lessthan symmetrical interconnections and/or as electro-mechanicalinterconnections shift or degrade over time. Interconnections may shiftdue to mechanical stress, vibration, thermal cycling, and/or materialdegradation. PIM can be an important interconnection qualitycharacteristic, as PIM generated by a single low quality interconnectionmay degrade the electrical performance of an entire RF system. Thus, thereduction of PIM via connector design is typically desirable.

It may be desirable to provide techniques for attaching connectors tocable conductors that exhibit low PIM and relatively low labormanufacturing.

SUMMARY

As a first aspect, embodiments of the invention are directed to acoaxial cable-connector assembly. The assembly comprises a coaxial cableand a right angle coaxial connector. The coaxial cable comprises: aninner conductor having a termination end, the termination end includinga bore; a dielectric layer that overlies the inner conductor; and anouter conductor that overlies the dielectric layer having a terminationend. The right angle coaxial connector comprises: an inner conductorbody comprising a post configured to mate with the inner conductor bodyof a mating coaxial cable jack, the inner conductor body furtherincluding a receptacle that receives the termination end of the innerconductor such that the post is generally perpendicular to the innerconductor; an outer conductor body configured to mate with the outerconductor body of the mating coaxial cable jack, the outer conductorbody being electrically connected with the termination end of the outerconductor; and an expansion member inserted into the bore of thetermination end of the inner conductor, the expansion member being sizedand configured to radially expand the termination end of the innerconductor.

As a second aspect, embodiments of the invention are directed to a rightangle coaxial connector assembly, comprising: (a) an inner conductorbody configured to mate with the inner conductor body of a matingcoaxial cable connector, the inner conductor body including a post thatdefines a first longitudinal axis and a receptacle configured to receivean inner conductor of a coaxial cable; (b) an outer conductor bodyconfigured to mate with the outer conductor body of a mating coaxialcable connector, the outer conductor body comprising: a generallycylindrical cable contact section having a second longitudinal axis thatis substantially normal to the first longitudinal axis and configured tobe electrically connected with the termination end of the outerconductor; a housing section attached to the cable contact section; anda generally cylindrical connector contact section attached to thehousing section having a longitudinal axis that is substantiallycoincident with the first longitudinal axis, the connector contactsection being configured to mate with the outer conductor body of themating coaxial cable connector; and (c) a dielectric spacer positionedto maintain electrical isolation between the connector contact sectionof the outer conductor body and the post of the inner conductor body.

As a third aspect, embodiments of the invention are directed to a methodof forming a right-angle coaxial cable-connector assembly. The methodinitially comprises the step of (a) providing a coaxial cablecomprising: an inner conductor having a termination end with a boreformed therein; a dielectric layer that overlies the inner conductor; anouter conductor that overlies the dielectric layer having a terminationend; and a jacket that overlies the outer conductor. The method alsocomprises the step of (b) providing a coaxial connector comprising: aninner conductor body configured to mate with the inner conductor body ofa mating coaxial cable connector, the inner conductor body including apost that defines a first longitudinal axis and a receptacle configuredto receive an inner conductor of a coaxial cable, wherein the receptacleincludes a hole; an outer conductor body configured to mate with theouter conductor body of a mating coaxial cable connector, the outerconductor body comprising: a housing section attached to the cablecontact section, wherein the housing section includes an access holealigned on a second longitudinal axis that is substantially normal tothe first longitudinal axis; and a dielectric spacer positioned tomaintain electrical isolation between the outer conductor body and thepost of the inner conductor body. The method further comprises the stepsof (c) inserting the coaxial cable through the cable contact section ofthe outer conductor body, such that the termination end of the innerconductor of the coaxial cable is inserted into the hole in thereceptacle of the inner conductor body; and (d) inserting an expansionmember through the access hole in the housing section into the bore ofthe inner conductor, such that the termination end of the innerconductor expands into electrical contact with the receptacle.

As a fourth aspect, embodiments of the invention are directed to anassembly comprising: a first member including a first receptacle; asecond member including a second receptacle that receives the receptacleof the first member; and an expansion member inserted into the firstreceptacle, the expansion member being sized and configured to radiallyexpand the first receptacle into contact with the second receptacle,such contact being sufficient to form a press-fit joint between thefirst and second receptacles.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view of a right-angle cable-connector assemblyaccording to embodiments of the present invention.

FIG. 2 is a side section view of a portion of the assembly of FIG. 1.

FIG. 3 is a top section of the assembly of FIG. 1.

FIG. 4 is a perspective view of the outer conductor body of the assemblyof FIG. 1.

FIG. 5 is a perspective view of the connector end of the inner and outerconductors of the cable of the assembly of FIG. 1.

FIG. 6 is a perspective view of the assembly of FIG. 1 prior to theinsertion of the dowel in the bore of the inner conductor of the cable,with the outer conductor body and insulator removed for clarity.

FIG. 7 is a perspective view of the dowel of the assembly of FIG. 1.

FIGS. 8A-8C are section views of alternative embodiments of dowelssuitable for use in the assembly of FIG. 1.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

The present invention is described with reference to the accompanyingdrawings, in which certain embodiments of the invention are shown. Thisinvention may, however, be embodied in many different forms and shouldnot be construed as limited to the embodiments that are pictured anddescribed herein; rather, these embodiments are provided so that thisdisclosure will be thorough and complete, and will fully convey thescope of the invention to those skilled in the art. It will also beappreciated that the embodiments disclosed herein can be combined in anyway and/or combination to provide many additional embodiments.

Unless otherwise defined, all technical and scientific terms that areused in this disclosure have the same meaning as commonly understood byone of ordinary skill in the art to which this invention belongs. Theterminology used in the above description is for the purpose ofdescribing particular embodiments only and is not intended to belimiting of the invention. As used in this disclosure, the singularforms “a”, “an” and “the” are intended to include the plural forms aswell, unless the context clearly indicates otherwise. It will also beunderstood that when an element (e.g., a device, circuit, etc.) isreferred to as being “connected” or “coupled” to another element, it canbe directly connected or coupled to the other element or interveningelements may be present. In contrast, when an element is referred to asbeing “directly connected” or “directly coupled” to another element,there are no intervening elements present.

Referring now to the drawings, a right angle connector-cable assembly,designated broadly at 5, is shown in FIGS. 1-3. The assembly 5 comprisesa coaxial cable 10 and a right angle plug 30, each of which is describedin detail below.

Referring to FIGS. 2, 3 and 5, the coaxial cable 10 includes an innerconductor 12, a dielectric layer 14 that circumferentially overlies thecentral conductor 12, an outer conductor 16 that circumferentiallyoverlies the dielectric layer 14, and a polymeric cable jacket 20 thatcircumferentially overlies the outer conductor 16. These components willbe well-known to those of skill in this art and need not be described indetail herein. Notably, the end of the inner conductor 12 includes abore 12 a (best seen in FIG. 5) at its termination end. FIGS. 3 and 5illustrate that the outer conductor 16 may be of a corrugated profile;alternatively, the outer conductor 16 may have a smooth, braided or foilprofile. All of these outer conductor configurations are known to thoseof skill in this art and need not be described in detail herein.

Referring to FIGS. 1-4 and 6, the plug 30 includes an inner conductorbody 32 and an outer conductor body 34. As can be seen in FIGS. 1, 2 and4, the inner conductor body 32 is generally cylindrical and comprises apost 41 that is configured to mate with the inner conductor body of amating jack. A ridge 49 extends radially outwardly from the post 41 nearthe swaged or chamfered tip 47. A finger 42 with a step 45 extends fromone end of the post 41; a contact block 43 or other receptacle with avertical hole 44 extends from the end of the finger 42.

Referring now to FIGS. 1-4, the outer conductor body 34 includes a cablecontact sleeve 52 having three grooves 53. A housing section 54 restsatop the cable contact sleeve 52, forming a shoulder 51. The housingsection includes side walls 55, a rear wall 56, and a ceiling 57 with anaccess hole 58. A connector contact section 59 extends away from thehousing section 54 opposite the rear wall 56. A dielectric spacer 62fills an inner portion of the connector contact section 59 and maintainsphysical and electrical separation of the inner conductor body 32 andthe outer conductor body 34. An annular mating ring 64 extends away fromthe spacer 62 and is configured to mate with a mating jack. A circularflange 66 extends radially outwardly from the connector contact section59 and provides a bearing surface 82 for interaction with a coupling nut80 and/or a retaining clip 78.

Referring now to FIG. 7, a generally cylindrical dowel 70 includes ends74, 76 that are chamfered. The dowel 70 is sized to be slightly largerthan the bore 12 a of the inner conductor 12 of the cable 10. Also, aplug 92 is sized to fit within and seal the access hole 58 of theceiling 57 (FIG. 2).

FIGS. 1-3 illustrate the assembled plug 30 and cable 10. The cablecontact sleeve 52 of the outer conductor body 34 fits over the outerconductor 16 of the cable 10, with the termination end of the outerconductor 16 abutting the shoulder 51 of the cable contact sleeve 52 toestablish an electrical connection. In some embodiments, this joint iscompleted via soldering. The inner conductor 12 extends into the cavityof the housing section 54. The hole 44 of the contact block 43 of theinner conductor body 32 receives the end of the inner conductor 12, suchthat the bore 12 a aligns with the access hole 58. The post 41 of theinner conductor body 32 extends through the dielectric spacer 62 andinto the space encircled by the mating ring 64. The right angle natureof the plug 30 is thus established by the perpendicular orientation ofthe post 41 and the inner conductor 12 and the housing section 54.

The inner conductor body 32 is attached to the inner conductor 12 of thecable 10 via the dowel 70. More specifically, the diameter of the dowel70 is slightly greater than the diameter of the bore 12 a of the innerconductor 12. The dowel 70 is passed through the access hole 58 of theceiling 57 of the housing section 55 (which is substantially collinearwith the bore 12 a), then driven into the bore 12 a of the innerconductor 12 (typically at high speed and/or under high pressure).Because the dowel 70 is larger than the bore 12 a, it forces the bore 12a radially outwardly to form a high pressure interference fit with theinner surface of the contact block 43 that attaches the inner conductor12 to the inner conductor body 32 and establishes electrical contacttherewith.

Those skilled in this art will appreciate that the dowel 70 may bereplaced with another variety of expansion member that causes the innerconductor 12 to expand radially outwardly sufficiently to form a jointwith the contact block 43 of the inner conductor body 32. Also, thedowel or other expansion member may have a smooth surface, or it mayhave a textured or roughened surface. For example, the dowel's outersurface may be completely or partially knurled (e.g., both ends may beknurled with a smooth central portion, or both ends may be smooth with aknurled central portion, one end may be smooth and the other knurled,etc.). Moreover, the dowel 70 may be partially or completely hollow,which may effectively “soften” the dowel 70, thereby providing apreselected balance of joint strength and stress on the bore 12 a of theinner conductor 12 of the cable 10, which may be particularly useful inaddressing material creep due to stress in the interference fit. Forexample, the dowel 70 may be hollow at one end (FIG. 8A) or at both ends(FIG. 8B). Alternatively, the dowel 70 may be narrower in a solidsection and thicker in a hollow section (FIG. 8C) to maintain contactbetween the dowel and the contact block 43 along the full length of thedowel 70. Other alternatives may also be suitable.

It should also be noted that, although the hole 44 in the contact block43 is shown as continuous, it may be discontinuous; for example, thecontact block 43 may include one or more slots to encourage radialexpansion. Receptacles other than the contact block 43 and or hole 44may also be suitable for use with the plug 30.

It can thus be seen that connectors according to embodiments of thisinvention can provide a cable-connector interface where the clampingforce is provided by deflection/distortion of one of the members of themating interface. By using a high pressure interface rather thansoldering at this interface, PIM can be reduced significantly.

Those of skill in this art will appreciate that, although the plug 30 isillustrated herein, a jack or other connector may be suitable for usewith the concepts discussed above. Also, although a galvanic connectionis anticipated between the plug 30 and a mating jack, the concepts maybe employed with connectors designed for capacitive coupling (see, e.g.,U.S. patent application Ser. No. 14/303,745, filed Jun. 13, 2014, thedisclosure of which is hereby incorporated herein in its entirety).

It should also be noted that the arrangement for creating a press-fitjoint between the inner conductor 12 and the inner contact 32 with thedowel 70 may be applicable to other components or structures, includingother cable-connector assemblies as well as other structural members. Anexpansion member can be inserted into a first receptacle, wherein suchinsertion radially expands the first receptacle into contact with asecond receptacle in which the first receptacle resides. The radialexpansion can create a press-fit joint between the first and secondreceptacles.

The foregoing is illustrative of the present invention and is not to beconstrued as limiting thereof. Although exemplary embodiments of thisinvention have been described, those skilled in the art will readilyappreciate that many modifications are possible in the exemplaryembodiments without materially departing from the novel teachings andadvantages of this invention. Accordingly, all such modifications areintended to be included within the scope of this invention as defined inthe claims. The invention is defined by the following claims, withequivalents of the claims to be included therein.

That which is claimed is:
 1. An electrical connector assemblycomprising: an elongate first member including a first receptacle at oneend thereof, the first member defining a first axis, and the firstreceptacle defining a second axis parallel with the first axis; anelongate second member including a second receptacle at one end thereofthat receives the receptacle of the first member, the second memberdefining a third axis perpendicular to the first and second axes, andthe second receptacle defining a fourth axis parallel with the first andsecond axes; and an expansion member inserted into the first receptacle,the expansion member being sized and configured to radially expand thefirst member into contact with the second receptacle, such contact beingsufficient to form a press-fit joint between the first and secondmembers; wherein the first member is an inner conductor of a coaxialcable, and the second member is an inner contact of a coaxial connector.2. The electrical connector assembly defined in claim 1, furthercomprising a housing in which the first and second receptacles reside,and wherein the housing includes an access hole through which the firstand second axes pass.
 3. The electrical connector assembly defined inclaim 2, wherein the housing is attached to the first and secondmembers.
 4. The electrical connector assembly defined in claim 1,wherein the expansion member has a tapered end that is inserted into thefirst receptacle.
 5. A method of forming a press-fit joint of anelectrical connector between a first member and a second member,comprising the steps of: providing an elongate first member including afirst receptacle at one end thereof, the first member defining a firstaxis, and the first receptacle defining a second axis parallel with thefirst axis; providing an elongate second member including a secondreceptacle at one end thereof, the second member defining a third axisperpendicular to the first and second axes, and the second receptacledefining a fourth axis parallel with the first and second axes;inserting the first receptacle of the first member in the secondreceptacle of the second member; and inserting an expansion member intothe first receptacle, the expansion member being sized and configured toradially expand the first member into contact with the secondreceptacle, such contact being sufficient to forma press-fit jointbetween the first and second members; wherein the first member is aninner conductor of a coaxial cable, and the second member is an innercontact of a coaxial connector.
 6. The method defined in claim 5,further comprising a housing in which the first and second receptaclesreside, and wherein the housing includes an access hole through whichthe first and second axes pass.
 7. The method defined in claim 6,wherein the housing is attached to the first and second members prior tothe insertion of the expansion member.
 8. The method defined in claim 6,wherein the housing is attached to the second member prior to theinsertion of the first receptacle.
 9. The method defined in claim 5,wherein the expansion member has a tapered end that is inserted into thefirst receptacle.